With label printers and the like that utilize rolled pint media, often a shift in the print position on a label often drifts over the course of a long print job. The shift in the print position is due to the change in diameter of the roll of print media as the labels are pulled from the roll by spring force for printing. The pulling force on a new roll of print media differs from that of a used roll (due to the different diameter of the print media). In existing printers, there is no mechanism to manage this changing force. As a result, print can shift over the course of a long print job.
Referring to FIG. 1, an example is shown of how printing degrades from the first few labels 20, 22 and 24 affixed to a label release liner 28 in a print job to labels later in a print job (i.e., such as 1000 labels later) such as labels 30 and 32 where the printed text may no longer align within the label boundaries. In this illustration, the labels and liner move through the printer in the direction shown by arrow 26. Such drift in printing is wasteful and may require that all or portions of a print job be repeated. At the end of a very long print job, the labels may be useless.
Therefore, a need exists for a mechanism to improve the precision of print alignment for long print jobs.